EP0254911B1 - Rectifier circuit and method for its controling - Google Patents

Rectifier circuit and method for its controling Download PDF

Info

Publication number
EP0254911B1
EP0254911B1 EP87109676A EP87109676A EP0254911B1 EP 0254911 B1 EP0254911 B1 EP 0254911B1 EP 87109676 A EP87109676 A EP 87109676A EP 87109676 A EP87109676 A EP 87109676A EP 0254911 B1 EP0254911 B1 EP 0254911B1
Authority
EP
European Patent Office
Prior art keywords
voltage
static
converter
transformer
quadrant
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP87109676A
Other languages
German (de)
French (fr)
Other versions
EP0254911A1 (en
Inventor
Birger Gotaas
Berislav Knaffl
Peter Knapp
Alfred-Christophe Rufer
Urs Zürcher
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BBC Brown Boveri AG Switzerland
Original Assignee
BBC Brown Boveri AG Switzerland
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BBC Brown Boveri AG Switzerland filed Critical BBC Brown Boveri AG Switzerland
Priority to AT87109676T priority Critical patent/ATE77019T1/en
Publication of EP0254911A1 publication Critical patent/EP0254911A1/en
Application granted granted Critical
Publication of EP0254911B1 publication Critical patent/EP0254911B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/49—Combination of the output voltage waveforms of a plurality of converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/02—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc
    • H02M5/04—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters
    • H02M5/22—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M5/25—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
    • H02M5/27—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means for conversion of frequency
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/145—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
    • H02M7/155—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
    • H02M7/19—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only arranged for operation in series, e.g. for voltage multiplication

Definitions

  • the invention is based on a method for controlling a converter circuit and a converter circuit for executing the method according to the preamble of claims 1 and 4.
  • the invention also relates to uses of the converter circuit.
  • the invention relates to a prior art, as is known from US-A-4,159,513.
  • a DC voltage is converted into a sinusoidal AC voltage by means of a specially designed transformer and several converters.
  • the DC voltage is switched to the partial transformers with the help of the individual converters and added up to a sinusoidal, step-shaped AC voltage on the primary side of the windings connected in series.
  • the partial transformers have their own magnetic cores.
  • the invention solves the problem of specifying a converter circuit of the type mentioned at the outset and a method for its operation which manage with less energy losses and ensure better protection.
  • the amplitude of this AC voltage is formed by stepwise addition and / or subtraction of partial voltages of the same amplitude.
  • the beginning and end of each voltage level are staggered in time so that the step shape created by the voltage levels is adapted to the sinusoidal shape.
  • Each partial voltage is generated by a special partial voltage source.
  • the partial voltage sources are switched off in the same order as they were switched on to form the staircase shape.
  • An advantage of the invention is that much smaller wiring losses of the converter result. This results in better converter efficiency. Wiring and cooling of the converter can be implemented more easily and cheaply. Another advantage is that no increased inductance is required at the AC output of the converter.
  • the voltage summing transformer can be built with a short-circuit voltage of the order of 5% - 13% that is common for converter transformers. The reduction of the short-circuit voltage allows a cheaper design and above all lower copper losses of the transformer with the same dimensioning criteria.
  • the thyristors and four-quadrant actuator diodes there are also somewhat lower losses of the thyristors and four-quadrant actuator diodes.
  • the reduction of losses is shown using the example of a 700 kVA actuator, which was configured for power consumption from the 16 2/3 Hz rail network in a locomotive type and is clocked at a frequency of 11 x 16 2/3 Hz.
  • the semiconductor losses are approximately 3.2 kW and the wiring losses approximately 10 kW. If the same actuator switches on and off only once in the 16 2/3 Hz half-period, the wiring losses are approx. 11 times smaller, ie they are only approx. 0.9 kW.
  • a voltage summing transformer Tr consists of 13 identically constructed and dimensioned partial transformers Tr1, Tr2 ... Tr13, each of which has its own transformer core, which is not magnetically coupled to one another.
  • Each sub-transformer Tr1 ... Tr13 has a winding 1 on the line side and a winding 2 on the converter side.
  • the line-side windings 1 of the part-transformers Tr1 - Tr13 are connected in series and connected to the rail network N1 at the ends by means of terminals 3 and 4.
  • Each converter-side winding 2 of a partial transformer Tr1 ... Tr13 is connected via AC voltage connections 6 and 7 to a four-quadrant regulator Q1 or Q2 ... Q13 and additionally to a thyristor short-circuiter or AC switch 5 with antiparallel thyristors. 8 denotes "+” poles and 9 "-" poles the four-quadrant positions Q1 ... Q13.
  • a DC voltage intermediate circuit 10 has a DC voltage support capacitor 11 between its "+” and "-” branches and also a suction circuit with a series circuit comprising a suction circuit capacitor 12 and a suction circuit reactor 13.
  • the natural frequency of the suction circuit is tuned to twice the frequency of the rail network, ie to 33 1/3 Hz, so that power pulsations that occur when the rail network N1 is fed can only be transmitted to the three-phase 50 Hz national network N2 to a tolerable extent.
  • a smoothing choke 14 is provided, which on the one hand with each "+” pole 8 of the four-quadrant converter Q1 ... Q13 and on the other hand with the "-" branch of a converter 15 and with the "+" - Branch of a converter 15 ⁇ is connected.
  • the "-" branch of the DC voltage intermediate circuit 10 is connected on the one hand to all "-" poles 9 of the four-quadrant converter Q1 ...
  • the converters 15 and 15 ⁇ are mutually anti-parallel, network-commutated bridge rectifiers with thyristors in the bridge branches.
  • the AC connections of these converters 15 and 15 ⁇ are connected to the AC network N2 via a converter transformer 16.
  • the four-quadrant actuator has four bridge branches, each with a GTO thyristor T1 ... T4 that can be switched off per bridge branch.
  • the thyristors T1 and T2 and on the other hand the thyristors T3 and T4 are connected in series, the anodes of the thyristors T1 and T3 with the "+" pole 8 via fuses 21a and 21b and the cathodes of the thyristors T2 and T4 with the "-" - Pol 9 are connected via fuses 21c and 21d.
  • a diode D1 ... D4 is connected antiparallel to each of the thyristors T1 ... T4. Furthermore, each thyristor T1 ...
  • T4 an identically constructed thyristor circuit or a shutdown relief circuit 17.
  • the switch-off relief circuit 17 has a wiring diode 18 in series with a wiring capacitor 20, the wiring diode 18 and the thyristor, for example T3, having the same polarity.
  • a wiring resistor 19 is connected in parallel with the wiring diode.
  • the connection points of the thyristors T1 and T2 are connected to the AC voltage connection 6 and the connection points of the thyristors T3 and T4 to the AC voltage connection 7.
  • U Q denotes the AC voltage and i Q the AC current of the four-quadrant actuator.
  • the frequency converter described in connection with Fig. 1 is suitable for energy transmission from a three-phase national network N2 to a single-phase rail network N1 and vice versa and for a power of e.g. 10 MW. If energy is only to be transferred from the state network N2 to the rail network N1, the converter 15 ⁇ can be omitted.
  • the 13th four-quadrant actuator Q13 is provided as an instantaneous reserve, the thyristors of which remain blocked and the AC switch 5 is continuously switched on or one of the two thyristors of the AC switch 5 is continuously conductive.
  • the formation of the 16 2/3 Hz AC voltage U1 arises from the summation of the voltages induced in the individual network-side windings 1 of the voltage summing transformer Tr, as can be seen from FIGS. 3 and 4.
  • the series connection of all windings 1 on the line side of the voltage summing transformer Tr has the effect that at a current i1 through the windings on the line side, a current must flow simultaneously in all windings 2 on the converter side. If all the winding pairs are the same (same number of turns and the same ratio), the current in all converter-side windings 2 must have the same size and the same polarity.
  • the switching states Z1 ... Z8 of a four-quadrant actuator according to FIG. 2 are first defined, specifying the direction of the current flow. For the sake of simplicity, from left to right, only the reference numerals of the components and input terminals or poles of the four-quadrant actuator that flow through one after the other are given.
  • Switching state Z1 U Q > 0, i Q > 0 Current flow direction: 8 - 21a - T1 - 2 - T4 - 21d - 9
  • Switching state Z2 U Q > 0, i Q ⁇ 0 Current flow direction: 9 - 21d - D4 - 2 - D1 - 21a - 8
  • Switching state Z3 U Q ⁇ 0, i Q > 0 Current flow direction: 9 - 21c - D2 - 2 - D3 - 21b - 8
  • Switching state Z4 U Q ⁇ 0, i Q ⁇ 0 Current flow direction: 8 - 21b - T3 - 2 - T2 - 21c - 9
  • Switching state Z5: U Q 0, i Q > 0 Current flow direction: T1 - 2 - D3 - 21b - 21a - T1
  • a voltage summing transformer Tr with only five sub-transformers Tr1-Tr5 and associated five four-quadrant actuators Q1-Q5 are used as a basis.
  • the translation of the winding pairs 1 and 2 of the partial transformers Tr1 - Tr5 is 1: 1.
  • alternating current i and alternating voltage U are plotted on the ordinate and time t is plotted in arbitrary units on the abscissa.
  • the mains-side alternating voltage U1 of the voltage summing transformer Tr is formed in stages, the course of the added voltage stages formed by means of the four-quadrant controllers Q1-Q5 being formed in such a way that the sum approximates a sinusoidal shape.
  • the alternating current i1 is out of phase with the alternating voltage U1 by 30 °.
  • the four-quadrant controller Q2 changes from the switching state Z5 or Z6 by blocking the conductive thyristors T1 or T4 to the switching state Z2, cf. Fig. 3c, corresponding to the second voltage level in Fig. 3a.
  • the alternating current i1 changes its sign from "-" to "+”, so that the four-quadrant actuators Q1 and Q2 change from the switching state Z2 to the switching state Z1 and the thyristors T1 and T4 replace the diodes D1 and D4 to conduct the alternating current i Q take over.
  • the four-quadrant Q3 switches. Fig.
  • the four-quadrant switches Q1 or Q2 from the switching state Z7 or Z8 to the switching state Z3 and after the zero crossing of the alternating current i1 at the time t11 to the switching state Z4.
  • the four-quadrant controllers Q3 ... Q5 change from switching state Z7 or Z8 to switching state Z4 at times t11 ... t13.
  • the four-quadrant controllers Q1 ... Q5 change to the switching state Z5 or Z6.
  • areas hatched in the left in FIGS. 4b - 4f indicate switching states in four-quadrant actuators in which only diodes conduct. In right-hatched areas, only thyristors conduct the current.
  • the four-quadrant actuators Q1-Q4 are switched in succession from the switching state Z4 to the switching state Z2.
  • the alternating current i1 changes its sign from "-" to "+”
  • the four-quadrant controllers Q1 - Q4 change from the diode-conducting switching state Z2 to the thyristor-conducting switching state Z1.
  • the four-quadrant controller Q5 changes from the thyristor-conducting switching state Z4 to the diode-conducting switching state Z2.
  • the four-quadrant controller Q5 changes from the switching state Z2 to the switching state Z1.
  • the thyristors are switched off in succession, so that these four four-quadrant actuators pass into the switching state Z3.
  • the alternating current i1 changes its sign from "+" to "-"
  • the four-quadrant controllers Q1-Q4 changing to the switching state Z4 and the four-quadrant controller Q5 to the switching state Z2.
  • the quadrant quadrant Q5 also switches to the switching state Z4.
  • the operation of the four-quadrant controller according to FIG. 4 has the advantage over that of FIG. 3 that each four-quadrant controller is only switched on and off once during a period of the AC voltage U1. This reduces the energy losses in the four-quadrant controller.
  • the thyristor circuit 17, in particular the circuit resistor 19, can be designed for a lower power. The effort for cooling the semiconductor components is reduced. The control of the thyristors is easier.
  • the disadvantage is the lower number of voltage levels, which results in poorer adaptation to the desired sinusoidal shape of the AC voltage U1 to be generated. With a sufficient number of four-quadrant digits and with large total outputs, this problem is not significant. Another disadvantage is the greater energy loss in the iron parts of the transformers Tr1 ...
  • Tr13 since the four-quadrant actuators work without a zero-voltage operating state. As a result, each sub-transformer must practically always be loaded up to the nominal inductance. At low frequencies, such as 16 2/3 Hz, iron losses are less important. Comparatively larger energy losses occur in the power lines or busbars between the four-quadrant actuators Q1 - Q13 and the DC voltage intermediate circuit 10. In contrast to this, in the operating mode according to FIG. 3, no current flows to the intermediate circuit in the zero voltage switching states Z5-Z8.
  • a step-shaped voltage curve from 0 to the amplitude value can be formed in the network-side windings 1 of the voltage summing transformer Tr.
  • the reduction of the induced total voltage in the network-side windings 1 of the voltage summing transformer Tr from the amplitude value to zero is carried out by switching off the thyristors of those four-quadrant actuators which change the voltage polarity in the network-side windings of the associated winding pairs and thus to reduce the overall voltage.
  • the negative half wave will formed in accordance with the positive, the thyristors and blocking diodes of the four-quadrant actuators responsible for the negative current half-oscillation then becoming active.
  • each current zero crossing will always require a change in the current combination of the four-quadrant actuators with respect to current carrying through thyristors or blocking diodes.
  • a change in the mains current i1 is always associated with a rigidly coupled current change in all partial transformer winding pairs 1, 2. Accordingly, the voltage summing transformer Tr can be operated with a normal short circuit voltage of e.g. 5% can be built, whereby the current shape is no worse than that of an ordinary four-quadrant converter, which is equipped with a transformer with an increased short-circuit voltage of e.g. 30% is coupled and works in the way of the undershoot method. This allows transformer costs and copper losses to be reduced, which leads to an improvement in the overall efficiency.
  • the induced instantaneous total voltage value in the line-side windings 1 of the voltage summing transformer Tr changes according to 1/6 of the amplitude value.
  • This relatively small voltage jump must cause a change in the current in all windings of the voltage summing transformer Tr. Accordingly, the leakage inductances of all windings become the changes in current slow it down.
  • the system described here also allows the possibility of finely regulating the step-like tension in addition to the formation thereof.
  • at least one of the four-quadrant controllers in the usual design for clock operation, i.e. with complex wiring (e.g. the reserve level).
  • complex wiring e.g. the reserve level.
  • the alternating voltage U1 can also be regulated without clocking one of the four-quadrant actuators by extending the current carrying time of individual stages. However, this causes a higher harmonic component in the induced fundamental voltage oscillation.
  • a thyristor short-circuiting device 5 is installed for each current transformer side 2 for both current directions.
  • the thyristors of the short-circuiting device 5 must in any case have automatic, self-igniting emergency ignition circuits, which make the short-circuiting device automatically conductive when a predetermined maximum voltage is exceeded.
  • This maximum voltage must be somewhat higher than the maximum operating voltage of the DC link 10.
  • the realization of the emergency ignition circuits is usually, as is generally known, solved by means of breakover diodes, which become conductive when a certain voltage is reached and ignite the thyristor via the normal ignition circuit.
  • the short-circuiting thyristors can be equipped with additional ignition circuits, which allow the desired ignition at any time.
  • the AC switch 5 is switched on during the corresponding time intervals.
  • the ignition signals for the four-quadrant actuators otherwise required for the switching states Z5 - Z8 are omitted.
  • the level of the AC voltage of a four-quadrant controller is either regulated by the DC link voltage Ud, for example, by gate control of the mains-operated 50 Hz feed converter 15 or by a single one of the four-quadrant controllers, which operates in clock mode at a higher frequency.
  • the control of the remaining four-quadrant actuators is operated by another control which is responsible for the voltage form and phase position at the network-side output of the voltage summing transformer Tr.
  • the converter circuit according to the invention is for energy transmission in both directions, i.e. from alternating voltage network N1 to alternating voltage network N2 and vice versa, preferably in the power range from 5 MW to 20 MW. Both networks can of course be multi-phase.
  • a voltage summing transformer Tr with partial transformers Tr1 ... Tr13 and associated converters Q1 ... Q13 and AC switches 5 must be provided for each phase of the alternating current. It is also possible to use more or fewer than 13 sub-transformers per voltage summing transformer Tr.
  • the converter circuit can also be used for frequency converters of three-phase networks, e.g. 50 Hz / 60 Hz or 60 Hz / 25 Hz etc.
  • GTO thyristors which can be switched off or, for smaller currents, transistors.
  • GTO thyristors in the four-quadrant controller ordinary thyristors with quenching circuits or transistors can of course be used. If required, several thyristors can be connected in series and / or in parallel.
  • the converter circuit Regardless of the direction of energy transmission, the converter circuit enables power transmission in the capacitive and inductive range, i.e. it can also be used as a reactive power compensator.
  • the converter circuit can be operated in parallel with other voltage sources in the network.
  • the converter circuit can work from practically zero to full load without drastically reducing efficiency and without significantly increasing the harmonic content.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Ac-Ac Conversion (AREA)
  • Selective Calling Equipment (AREA)
  • Remote Monitoring And Control Of Power-Distribution Networks (AREA)
  • Invalid Beds And Related Equipment (AREA)
  • Coupling Device And Connection With Printed Circuit (AREA)
  • Emergency Protection Circuit Devices (AREA)
  • Exchange Systems With Centralized Control (AREA)
  • Details Of Television Scanning (AREA)
  • Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
  • Control Of Electrical Variables (AREA)

Abstract

A static converter circuit has a voltage summing transformer (Tr-Tr13) with several part transformers (Tr1-Tr13) the static-converter-side winding of which are connected via one four-quadrant actuator each to a direct-voltage link circuit. The four-quadrant actuators are single-phase bridge circuits with one GTO thyristor each and a diode, which is antiparallel thereto, per bridge branch. The static-converter-side windings of the part transformers can be short circuited in each case by means of an alternating-current circuit breaker with antiparallel-connected thyristors. Each part transformer has a separate core. The power-system-side windings of the power transformers are connected in series and are connected at their ends to a railroad power system with 162/3-Hz. The direct-voltage link circuit is connected via power-system-commutated static converters and a static converter transformer to a national power system with 50 Hz. For generating an approximately sinusoidal alternating voltage part voltages of equal amplitude which are supplied by the part transformers are added and/or subtracted step-by-step in the voltage summing transformer. Each thyristor of a four-quadrant actuator is turned-on and turned-off at the most, twice per period of the alternating voltage. This reduces power losses and expenditures for cooling the semiconductor components. The static converter circuit is suitable for frequency converters and reactive-power compensators.

Description

TECHNISCHES GEBIETTECHNICAL AREA

Bei der Erfindung wird ausgegangen von einem Verfahren zum steuern einer Stromrichterschaltung und von einer Stromrichterschaltung zur Ausführung des Verfahrens nach dem Oberbegriff der Patentansprüche 1 und 4. Die Erfindung betrifft auch Verwendungen der Stromrichterschaltung.The invention is based on a method for controlling a converter circuit and a converter circuit for executing the method according to the preamble of claims 1 and 4. The invention also relates to uses of the converter circuit.

STAND DER TECHNIKSTATE OF THE ART

Mit den Oberbegriffen nimmt die Erfindung auf einen Stand der Technik Bezug, wie er aus der US-A-4,159,513 bekannt ist. Dort wird zur Verbesserung des Reversierbetriebes eines Motors mittels eines speziell ausgebildeten Transformators und mehrerer Stromrichter eine Gleichspannung in eine sinusförmige Wechselspannung umgewandelt. Dazu wird mit Hilfe der einzelnen Stromrichter die Gleichspannung auf die Teiltransformatoren geschaltet und auf der Primärseite der in Reihe geschalteten Wicklungen zu einer sinusförmigen, treppenförmigen Wechselspannung aufsummiert. Die Teiltransformatoren weisen eigene magnetische Kerne auf.With the preambles, the invention relates to a prior art, as is known from US-A-4,159,513. In order to improve the reversing operation of a motor, a DC voltage is converted into a sinusoidal AC voltage by means of a specially designed transformer and several converters. For this purpose, the DC voltage is switched to the partial transformers with the help of the individual converters and added up to a sinusoidal, step-shaped AC voltage on the primary side of the windings connected in series. The partial transformers have their own magnetic cores.

Schutzmassnahmen beim Ausfall eines Stromrichters sind nicht vorgesehen.Protective measures in the event of a converter failure are not provided.

Aus der Schweizer Firmenzeitschrift "Brown Boveri Mitteilungen" 12 (1979), S. 763 - 777 ist es bekannt, Umrichterlokomotiven mit Drehstrom-Asynchronmotoren aus einem 16 2/3-Hz-Bahnnetz über einen Gleichspannungszwischenkreis zu speisen. Die Gleichspannung wird dabei aus dem Bahnnetz mittels eines Stromsummiertransformators, der mehrere Teilwicklungen mit gemeinsamem Transformatorkern aufweist, und mittels mehrerer an diese Teilwicklungen angeschlossener Vierquadrantensteller gewonnen. Die Vierquadrantensteller werden im Unterschwingungsverfahren betrieben und benötigen auf der Wechselstromseite eine relativ grosse Induktivität, welche mit Hilfe einer hohen Kurzschlusspannung des Transformators von ca. 30 % realisiert wird. Derartige Transformatoren sind teuer und weisen hohe Energieverluste in den Kupferteilen auf.From the Swiss company magazine "Brown Boveri Mitteilungen" 12 (1979), pp. 763 - 777, it is known to feed converter locomotives with three-phase asynchronous motors from a 16 2/3 Hz rail network via a DC link. The DC voltage is thereby from the rail network by means of a current summing transformer, which has several partial windings with a common transformer core, and by means of several four-quadrant controllers connected to these partial windings. The four-quadrant actuators are operated using the undershoot method and require a relatively large inductance on the AC side, which is achieved with the help of a high short-circuit voltage of the transformer of approx. 30%. Such transformers are expensive and have high energy losses in the copper parts.

In der deutschen Zeitschrift "Elektrische Bahnen" 6 (1974) S. 135 - 142 sind Schaltung und Betrieb eines Vierquadrantenstellers beschrieben. Diese Schaltung erlaubt es, ein Wechselstromnetz mit einem Gleichspannungszwischenkreis (Zwischenkreis mit eingeprägter Spannung) zu verbinden. Zwei Vierquadrantensteller, die über je eine Transformatorsekundärwicklung netzseitig parallelgeschaltet sind, arbeiten auf einen gemeinsamen Zwischenkreis. Die Steuerung erfolgt durch phasenversetztes Takten der beiden Vierquadrantensteller mit einer Frequenz von ca. 11 · 16 2/3 Hz. Durch diese relativ hohe Taktfrequenz entstehen hohe Energieverluste in Beschaltungsbauelementen der Vierquadrantensteller.The circuit and operation of a four-quadrant actuator are described in the German magazine "electric railways" 6 (1974) pp. 135-142. This circuit allows an AC network to be connected to a DC link (DC link with impressed voltage). Two four-quadrant actuators, each connected in parallel on the mains side via a transformer secondary winding, work on a common intermediate circuit. The control is carried out by phase-shifted clocking of the two four-quadrant actuators with a frequency of approx. 11 · 16 2/3 Hz. This relatively high clock frequency results in high energy losses in the circuit components of the four-quadrant actuators.

Darstellung der ErfindungPresentation of the invention

Der Erfindung, wie sie in den Ausprüchen 1-4 definiert ist, löst die Aufgabe, eine Stromrichterschaltung der eingangs genannten Art und ein Verfahren zu deren Betrieb anzugeben, die mit weniger Energieverlusten auskommen und einen besseren Schutz gewährleisten.The invention, as defined in claims 1-4, solves the problem of specifying a converter circuit of the type mentioned at the outset and a method for its operation which manage with less energy losses and ensure better protection.

Zur Erzeugung einer wenigstens annähernd sinusförmigen Wechselspannung mit einer vorgebbaren Frequenz wird die Amplitude dieser Wechselspannung durch stufenweise Addition und/oder Subtraktion von Teilspannungen gleicher Amplitude gebildet. Beginn und Ende jeder Spannungsstufe sind zeitlich so gestaffelt, dass die durch die Spannungsstufen erzeugte Treppenform der Sinusform angepasst ist. Jede Teilspannung wird durch eine besondere Teilspannungsquelle erzeugt. Die Teilspannungsquellen werden in derselben Reihenfolge abgeschaltet, wie sie zur Bildung der Treppenform eingeschaltet wurden.To generate an at least approximately sinusoidal AC voltage with a predeterminable frequency, the amplitude of this AC voltage is formed by stepwise addition and / or subtraction of partial voltages of the same amplitude. The beginning and end of each voltage level are staggered in time so that the step shape created by the voltage levels is adapted to the sinusoidal shape. Each partial voltage is generated by a special partial voltage source. The partial voltage sources are switched off in the same order as they were switched on to form the staircase shape.

Ein Vorteil der Erfindung besteht darin, dass viel kleinere Beschaltungsverluste des Stromrichters resultieren. Dadurch ergibt sich ein besserer Wirkungsgrad der Stromrichter. Beschaltung und Kühlung des Stromrichters können einfacher und billiger realisiert werden. Ein weiterer Vorteil besteht darin, dass keine erhöhte Induktivität am Wechselstromausgang des Stromrichters benötigt wird. Der Spannungssummiertransformator kann mit einer bei den Stromrichtertransformatoren üblichen Kurzschlussspannung in der Grössenordnung von 5 % - 13 % gebaut werden. Die Reduktion der Kurzschlusspannung erlaubt bei gleichen Dimensionierungskriterien eine billigere Ausführung und vor allem niedrigere Kupferverluste des Transformators.An advantage of the invention is that much smaller wiring losses of the converter result. This results in better converter efficiency. Wiring and cooling of the converter can be implemented more easily and cheaply. Another advantage is that no increased inductance is required at the AC output of the converter. The voltage summing transformer can be built with a short-circuit voltage of the order of 5% - 13% that is common for converter transformers. The reduction of the short-circuit voltage allows a cheaper design and above all lower copper losses of the transformer with the same dimensioning criteria.

Gemäss einer vorteilhaften Ausgestaltung der Erfindung ergeben sich ausserdem etwas geringere Verluste der Thyristoren und Dioden des Vierquadrantenstellers. Die Reduktion der Verluste wird am Beispiel eines 700-kVA-Stellers gezeigt, welcher für Stromentnahme aus dem 16 2/3-Hz-Bahnnetz in einem Lokomotivtyp projektiert wurde und mit einer Frequenz von 11 · 16 2/3 Hz getaktet wird. Bei Volllast betragen die Halbleiterverluste ca. 3,2 kW und die Beschaltungsverluste ca. 10 kW. Wenn der gleiche Steller nur einmal in der 16 2/3-Hz-Halbperiopde ein-und ausschaltet, sind die Beschaltungsverluste ca. 11 mal kleiner, d.h. sie betragen nur ca. 0,9 kW.According to an advantageous embodiment of the invention, there are also somewhat lower losses of the thyristors and four-quadrant actuator diodes. The reduction of losses is shown using the example of a 700 kVA actuator, which was configured for power consumption from the 16 2/3 Hz rail network in a locomotive type and is clocked at a frequency of 11 x 16 2/3 Hz. At full load, the semiconductor losses are approximately 3.2 kW and the wiring losses approximately 10 kW. If the same actuator switches on and off only once in the 16 2/3 Hz half-period, the wiring losses are approx. 11 times smaller, ie they are only approx. 0.9 kW.

Kurze Beschreibung der ZeichnungenBrief description of the drawings

Nachfolgend wird die Erfindung anhand von in Zeichnungen dargestellten Ausführungsformen näher erläutert. Es zeigen:

Fig. 1
ein Prinzipschaltbild eines vollstatischen Frequenzumrichters mit einer Stromrichterschaltung mit Spannungssummiertransformator und mehreren daran angeschlossenen Vierquadrantenstellern sowie Thyristor-Kurzschliessern,
Fig. 2
ein Prinzipschema eines Vierquadrantenstellers mit Thyristor-Kurzschliesser und stellerseitiger Wicklung des Spannungssummiertransformators gemäss Fig. 1,
Fig. 3a und 4a
den Zeitverlauf von Wechselstrom und Wechselspannung bei Stromrichterschaltungen gemäss den Fig. 1 und 2 mit unterschiedlicher Spannungsstufenzahl,
Fig. 3b - 3f und Fig. 4b - 4f
den Zeitverlauf von Schaltzuständen der fünf Stromrichterschaltungen, entsprechend dem Wechselstrom und der Wechselspannung der Fig. 3a bzw. 4a.
The invention is explained in more detail below with reference to embodiments shown in the drawings. Show it:
Fig. 1
a basic circuit diagram of a fully static frequency converter with a converter circuit with voltage summing transformer and several four-quadrant actuators connected to it as well as thyristor short-circuiters,
Fig. 2
1 shows a basic diagram of a four-quadrant actuator with thyristor short-circuiter and actuator-side winding of the voltage summing transformer according to FIG. 1,
3a and 4a
the time course of alternating current and alternating voltage in converter circuits according to FIGS. 1 and 2 with different number of voltage stages,
Figures 3b - 3f and 4b - 4f
the time course of switching states of the five converter circuits, corresponding to the alternating current and the alternating voltage of FIGS. 3a and 4a.

Wege zur Ausführung der ErfindungWays of Carrying Out the Invention

In Fig. 1 ist mit N1 ein einphasiges 16 2/3-Hz-Bahnnetz mit einer Wechselspannung U1 = 15 kV und mit N2 ein dreiphasiges 50-Hz-Landesnetz mit einer Wechselspannung U2 = 50 kV angedeutet. Ein Spannungssummiertransformator Tr besteht aus 13 gleich aufgebauten und dimensionierten Teiltransformatoren Tr1, Tr2 ... Tr13, die jeweils eigene, nicht miteinander magnetisch verkoppelte Transformatorkerne haben. Jeder Teiltransformator Tr1 ... Tr13 besitzt eine netzseitige Wicklung 1 und eine stromrichterseitige Wicklung 2. Die netzseitigen Wicklungen 1 der Teiltransformatoren Tr1 - Tr13 sind in Reihe geschaltet und endseitig mittels Klemmen 3 und 4 an das Bahnnetz N1 angeschlossen. Mit i1 ist der Wechselstrom durch die netzseitigen Wicklungen 1 bezeichnet. Jede stromrichterseitige Wicklung 2 eines Teiltransformators Tr1 ... Tr13 ist über Wechselspannungsanschlüsse 6 und 7 an einen Vierquadrantensteller Q1 bzw. Q2 ... Q13 und zusätzlich an einen Thyristor-Kurzschliesser bzw. Wechselstromschalter 5 mit antiparallelen Thyristoren angeschlossen. Mit 8 sind "+"-Pole und mit 9 "-"-Pole der Vierquadrantensteller Q1 ... Q13 bezeichnet. Ein Gleichspannungszwischenkreis 10 weist zwischen seinem "+"- und "-"-Zweig einen Gleichspannungsstützkondensator 11 und ferner einen Saugkreis mit einer Reihenschaltung aus einem Saugkreiskondensator 12 und einer Saugkreisdrossel 13 auf. Die Eigenfrequenz des Saugkreises ist auf die doppelte Frequenz des Bahnnetzes, d.h. auf 33 1/3 Hz abgestimmt, damit bei der Speisung des Bahnnetzes N1 entstehende Leistungspulsationen nur in einem tolerablen Ausmass auf das dreiphasige 50-Hz-Landesnetz N2 übertragen werden. Im "+"-Zweig des Gleichspannungszwischenkreises 10 ist eine Glättungsdrossel 14 vorgesehen, die einerseits mit jedem "+"-Pol 8 der Vierquadrantensteller Q1 ... Q13 und andererseits mit dem "-"-Zweig eines Stromrichters 15 und mit dem "+"-Zweig eines Stromrichters 15ʹ verbunden ist. Der "-"-Zweig des Gleichspannungszwischenkreises 10 ist einerseits mit allen "-"-Polen 9 der Vierquadrantensteller Q1 ... Q13 und andererseits mit dem "+"-Zweig des Stromrichters 15 und mit dem "-"-Zweig des Stromrichters 15ʹ verbunden. Die Stromrichter 15 und 15ʹ sind zueinander antiparallel geschaltete, netzkommutierte Brückengleichrichter mit Thyristoren in den Brückenzweigen. Die Wechselstromanschlüsse dieser Stromrichter 15 und 15ʹ sind über einen Stromrichtertransformator 16 mit dem Wechselspannungsnetz N2 verbunden.1 shows a single-phase 16 2/3 Hz rail network with an alternating voltage U1 = 15 kV and with N2 a three-phase 50 Hz state network with an alternating voltage U2 = 50 kV. A voltage summing transformer Tr consists of 13 identically constructed and dimensioned partial transformers Tr1, Tr2 ... Tr13, each of which has its own transformer core, which is not magnetically coupled to one another. Each sub-transformer Tr1 ... Tr13 has a winding 1 on the line side and a winding 2 on the converter side. The line-side windings 1 of the part-transformers Tr1 - Tr13 are connected in series and connected to the rail network N1 at the ends by means of terminals 3 and 4. The alternating current through the line-side windings 1 is designated i1. Each converter-side winding 2 of a partial transformer Tr1 ... Tr13 is connected via AC voltage connections 6 and 7 to a four-quadrant regulator Q1 or Q2 ... Q13 and additionally to a thyristor short-circuiter or AC switch 5 with antiparallel thyristors. 8 denotes "+" poles and 9 "-" poles the four-quadrant positions Q1 ... Q13. A DC voltage intermediate circuit 10 has a DC voltage support capacitor 11 between its "+" and "-" branches and also a suction circuit with a series circuit comprising a suction circuit capacitor 12 and a suction circuit reactor 13. The natural frequency of the suction circuit is tuned to twice the frequency of the rail network, ie to 33 1/3 Hz, so that power pulsations that occur when the rail network N1 is fed can only be transmitted to the three-phase 50 Hz national network N2 to a tolerable extent. In the "+" branch of the DC voltage intermediate circuit 10, a smoothing choke 14 is provided, which on the one hand with each "+" pole 8 of the four-quadrant converter Q1 ... Q13 and on the other hand with the "-" branch of a converter 15 and with the "+" - Branch of a converter 15ʹ is connected. The "-" branch of the DC voltage intermediate circuit 10 is connected on the one hand to all "-" poles 9 of the four-quadrant converter Q1 ... Q13 and on the other hand to the "+" branch of the converter 15 and to the "-" branch of the converter 15ʹ . The converters 15 and 15ʹ are mutually anti-parallel, network-commutated bridge rectifiers with thyristors in the bridge branches. The AC connections of these converters 15 and 15ʹ are connected to the AC network N2 via a converter transformer 16.

Der Aufbau eines der gleich aufgebauten, einphasigen Vierquadrantensteller Q1 ... Q13 ist in Fig. 2 zu erkennen. Gleiche Teile sind mit gleichen Bezugszeichen versehen.The structure of one of the same, single-phase four-quadrant controllers Q1 ... Q13 can be seen in Fig. 2. The same parts are provided with the same reference numerals.

Der Vierquadrantensteller weist vier Brückenzweige mit je einem abschaltbaren GTO-Thyristor T1 ... T4 je Brükkenzweig auf. Einerseits sind die Thyristoren T1 und T2 und andererseits die Thyristoren T3 und T4 in Reihe geschaltet, wobei die Anoden der Thyristoren T1 und T3 mit dem "+"-Pol 8 über Sicherungen 21a bzw. 21b und die Kathoden der Thyristoren T2 und T4 mit dem "-"-Pol 9 über Sicherungen 21c bzw. 21d verbunden sind. Antiparallel zu jedem der Thyristoren T1 ... T4 ist eine Diode D1 ... D4 geschaltet. Ferner weist jeder Thyristor T1 ... T4 eine gleich aufgebaute Thyristorbeschaltung bzw. einen Abschaltentlastungskreis 17 auf. Der Abschaltentlastungskreis 17 weist eine Beschaltungsdiode 18 in Reihe mit einem Beschaltungskondensator 20 auf, wobei die Beschaltungsdiode 18 und der Thyristor, z.B. T3, gleich gepolt sind. Parallel zur Beschaltungsdiode ist ein Beschaltungswiderstand 19 angeschlossen. Die Verbindungspunkte der Thyristoren T1 und T2 sind mit dem Wechselspannungsanschluss 6 und die Verbindungspunkte der Thyristoren T3 und T4 mit dem Wechselspannungsanschluss 7 verbunden. UQ bezeichnet die Wechselspannung und iQ den Wechselstrom des Vierquadrantenstellers.The four-quadrant actuator has four bridge branches, each with a GTO thyristor T1 ... T4 that can be switched off per bridge branch. On the one hand the thyristors T1 and T2 and on the other hand the thyristors T3 and T4 are connected in series, the anodes of the thyristors T1 and T3 with the "+" pole 8 via fuses 21a and 21b and the cathodes of the thyristors T2 and T4 with the "-" - Pol 9 are connected via fuses 21c and 21d. A diode D1 ... D4 is connected antiparallel to each of the thyristors T1 ... T4. Furthermore, each thyristor T1 ... T4 an identically constructed thyristor circuit or a shutdown relief circuit 17. The switch-off relief circuit 17 has a wiring diode 18 in series with a wiring capacitor 20, the wiring diode 18 and the thyristor, for example T3, having the same polarity. A wiring resistor 19 is connected in parallel with the wiring diode. The connection points of the thyristors T1 and T2 are connected to the AC voltage connection 6 and the connection points of the thyristors T3 and T4 to the AC voltage connection 7. U Q denotes the AC voltage and i Q the AC current of the four-quadrant actuator.

Der in Verbindung mit Fig. 1 beschriebene Frequenzumrichter ist für eine Energieübertragung aus einem dreiphasigen Landesnetz N2 in ein einphasiges Bahnnetz N1 und umgekehrt geeignet und für eine Leistung von z.B. 10 MW ausgelegt. Falls Energie nur aus dem Landesnetz N2 in das Bahnnetz N1 übertragen werden soll, kann der Stromrichter 15ʹ entfallen.The frequency converter described in connection with Fig. 1 is suitable for energy transmission from a three-phase national network N2 to a single-phase rail network N1 and vice versa and for a power of e.g. 10 MW. If energy is only to be transferred from the state network N2 to the rail network N1, the converter 15ʹ can be omitted.

Im Normalbetrieb sind nur 12 Vierquadrantensteller Q1 ... Q12 an der Bildung der 16 2/3-Hz-Wechselspannung beteiligt. Der 13. Vierquadrantensteller Q13 ist als Momentanreserve vorgesehen, wobei dessen Thyristoren gesperrt bleiben und der Wechselstromschalter 5 ständig eingeschaltet bzw. einer der beiden Thyristoren des Wechselstromschalters 5 ständig leitend ist. Die Bildung der 16 2/3-Hz-Wechselspannung U1 entsteht durch Summierung der in den einzelnen netzseitigen Wicklungen 1 des Spannungssummiertransformators Tr induzierten Spannungen, wie es aus den Fig. 3 und 4 hervorgeht.In normal operation, only 12 four-quadrant controllers Q1 ... Q12 are involved in the formation of the 16 2/3 Hz AC voltage. The 13th four-quadrant actuator Q13 is provided as an instantaneous reserve, the thyristors of which remain blocked and the AC switch 5 is continuously switched on or one of the two thyristors of the AC switch 5 is continuously conductive. The formation of the 16 2/3 Hz AC voltage U1 arises from the summation of the voltages induced in the individual network-side windings 1 of the voltage summing transformer Tr, as can be seen from FIGS. 3 and 4.

Die Reihenschaltung aller netzseitigen Wicklungen 1 des Spannungssummiertransformators Tr bewirkt, dass bei einem Strom i1 durch netzseitige Wicklungen gleichzeitig ein Strom in allen stromrichterseitigen Wicklungen 2 fliessen muss. Wenn alle Wicklungspaare gleich sind (gleiche Anzahl Windungen und gleiche Uebersetzung), muss auch der Strom in allen stromrichterseitigen Wicklungen 2 gleiche Grösse und gleiche Polarität haben.The series connection of all windings 1 on the line side of the voltage summing transformer Tr has the effect that at a current i1 through the windings on the line side, a current must flow simultaneously in all windings 2 on the converter side. If all the winding pairs are the same (same number of turns and the same ratio), the current in all converter-side windings 2 must have the same size and the same polarity.

Zur Erläuterung der Wirkungsweise der Stromrichterschaltung werden zunächst die Schaltzustände Z1 ... Z8 eines Vierquadrantenstellers gemäss Fig. 2 definiert unter Angabe der Richtung des Stromflusses. Der Einfachheit halber werden von links nach rechts nur die Bezugszeichen der nacheinander durchflossenen Bauelemente und Eingangsklemmen bzw. Pole des Vierquadrantenstellers angegeben.To explain the mode of operation of the converter circuit, the switching states Z1 ... Z8 of a four-quadrant actuator according to FIG. 2 are first defined, specifying the direction of the current flow. For the sake of simplicity, from left to right, only the reference numerals of the components and input terminals or poles of the four-quadrant actuator that flow through one after the other are given.

Schaltzustand Z1: UQ > 0, iQ > 0
Stromflussrichtung: 8 - 21a - T1 - 2 - T4 - 21d - 9
Schaltzustand Z2: UQ > 0, iQ < 0
Stromflussrichtung: 9 - 21d - D4 - 2 - D1 - 21a - 8
Schaltzustand Z3: UQ < 0, iQ > 0
Stromflussrichtung: 9 - 21c - D2 - 2 - D3 - 21b - 8
Schaltzustand Z4: UQ < 0, iQ < 0
Stromflussrichtung: 8 - 21b - T3 - 2 - T2 - 21c - 9
Schaltzustand Z5: UQ = 0, iQ > 0
Stromflussrichtung: T1 - 2 - D3 - 21b - 21a - T1
Schaltzustand Z6: UQ = 0, iQ > 0
Stromflussrichtung: T4 - 21d - 21c - D2 - 2 - T4
Schaltzustand Z7: UQ = 0, iQ < 0
Stromflussrichtung: T3 - 2 - D1 - 21a - 21b - T3
Schaltzustand Z8: UQ = 0, iQ < 0
Stromflussrichtung: T2 - 21c - 21d - D4 - 2 - T2
Switching state Z1: U Q > 0, i Q > 0
Current flow direction: 8 - 21a - T1 - 2 - T4 - 21d - 9
Switching state Z2: U Q > 0, i Q <0
Current flow direction: 9 - 21d - D4 - 2 - D1 - 21a - 8
Switching state Z3: U Q <0, i Q > 0
Current flow direction: 9 - 21c - D2 - 2 - D3 - 21b - 8
Switching state Z4: U Q <0, i Q <0
Current flow direction: 8 - 21b - T3 - 2 - T2 - 21c - 9
Switching state Z5: U Q = 0, i Q > 0
Current flow direction: T1 - 2 - D3 - 21b - 21a - T1
Switching state Z6: U Q = 0, i Q > 0
Current flow direction: T4 - 21d - 21c - D2 - 2 - T4
Switching state Z7: U Q = 0, i Q <0
Current flow direction: T3 - 2 - D1 - 21a - 21b - T3
Switching state Z8: U Q = 0, i Q <0
Current flow direction: T2 - 21c - 21d - D4 - 2 - T2

Die Wirkungsweise der Stromrichterschaltung wird nun anhand der Fig. 3 und 4 erläutert, wobei der Einfachheit halber ein Spannungssummiertransformator Tr mit nur fünf Teiltransformatoren Tr1 - Tr5 und zugehörigen fünf Vierquadrantenstellern Q1 - Q5 zugrundegelegt sind. Die Uebersetzung der Wicklungspaare 1 und 2 der Teiltransformatoren Tr1 - Tr5 sei 1:1.The operation of the converter circuit will now be explained with reference to FIGS. 3 and 4, for the sake of simplicity, a voltage summing transformer Tr with only five sub-transformers Tr1-Tr5 and associated five four-quadrant actuators Q1-Q5 are used as a basis. The translation of the winding pairs 1 and 2 of the partial transformers Tr1 - Tr5 is 1: 1.

In den Fig. 3a und 4a sind auf der Ordinate Wechselstrom i und Wechselspannung U und auf der Abszisse die Zeit t in willkürlichen Einheiten aufgetragen. Die netzseitige Wechselspannung U1 des Spannungssummiertransformators Tr wird stufenweise gebildet, wobei die mittels der Vierquadrantensteller Q1 - Q5 gebildeten, addierten Spannungsstufen in ihrem zeitlichen Verlauf so gebildet sind, dass sich in der Summe angenähert eine Sinusform ergibt. Der Wechselstrom i1 ist im gewählten Beispiel gegenüber der Wechselspannung U1 um 30° phasenverschoben.3a and 4a, alternating current i and alternating voltage U are plotted on the ordinate and time t is plotted in arbitrary units on the abscissa. The mains-side alternating voltage U1 of the voltage summing transformer Tr is formed in stages, the course of the added voltage stages formed by means of the four-quadrant controllers Q1-Q5 being formed in such a way that the sum approximates a sinusoidal shape. In the selected example, the alternating current i1 is out of phase with the alternating voltage U1 by 30 °.

In den Fig. 3b - 3f und 4b - 4f sind auf der Ordinate die Wechselspannung UQ der Vierquadrantensteller Q1 - Q5 und auf der Abszisse die Zeit t in Einheiten der Fig. 3a und 4a dargestellt.3b-3f and 4b-4f the AC voltage U Q of the four-quadrant generator Q1-Q5 is shown on the ordinate and the time t in units of FIGS. 3a and 4a on the abscissa.

Bei dem Ausführungsbeispiel gemäss Fig. 3, bei dem Thyristoren T1 und T4 bzw. T3 und T2 in diagonalen Brückenzweigen eines Vierquadrantenstellers Q1 - Q5 für den Zustand UQ = 0 nicht gleichzeitig gezündet werden, ist die Spannungsstufenzahl doppelt so gross wie bei dem Ausführungsbeispiel gemäss Fig. 4, bei dem die Thyristoren in diagonalen Brückenzweigen immer gleichzeitig gezündet werden.3, in which thyristors T1 and T4 or T3 and T2 in diagonal bridge branches of a four-quadrant converter Q1-Q5 for the state U Q = 0 are not fired simultaneously, the number of voltage stages is twice as large as in the exemplary embodiment according to Fig. 4, in which the thyristors in diagonal bridge branches are always fired simultaneously.

Bei dem Ausführungsbeispiel gemäss Fig. 3 erzeugen im Zeitpunkt t0 die Vierquadrantensteller Q2 - Q5 keine Wechselspannung UQ (Schaltzustände Z5 oder Z6), während der Vierquadrantensteller Q1 vom Schaltzustand Z5 oder Z6 in den Schaltzustand Z2 wechselt und eine Wechselspannung UQ = Ud über den Teiltransformator Tr1 auf die netzseitige Wicklung 1 des Spannungssummiertransformators Tr überträgt, entsprechend der ersten Spannungsstufe in Fig. 3a.In the exemplary embodiment according to FIG. 3, the four-quadrant controllers Q2-Q5 do not generate any AC voltage U Q (switching states Z5 or Z6) at the time t0, while the four-quadrant controller Q1 changes from the switching state Z5 or Z6 to the switching state Z2 and an AC voltage U Q = Ud via the Subtransformer Tr1 transfers to the line-side winding 1 of the voltage summing transformer Tr, corresponding to the first voltage stage in FIG. 3a.

Im Zeitpunkt t1 wechselt der Vierquadrantensteller Q2 vom Schaltzustand Z5 oder Z6 durch Sperren der leitenden Thyristoren T1 oder T4 in den Schaltzustand Z2, vgl. Fig. 3c, entsprechend der zweiten Spannungsstufe in Fig. 3a. Im Zeitpunkt t2 wechselt der Wechselstrom i1 sein Vorzeichen von "-" nach "+", so dass die Vierquadrantensteller Q1 und Q2 vom Schaltzustand Z2 in den Schaltzustand Z1 wechseln und die Thyristoren T1 und T4 anstelle der Dioden D1 und D4 die Leitung des Wechselstromes iQ übernehmen. Gleichzeitig schaltet der Vierquadrantensteller Q3 vgl. Fig. 3d, vom Schaltzustand Z5 oder Z6 in den Schaltzustand Z1, entsprechend der dritten Spannungsstufe in Fig. 3a. Die gleiche Umschaltung erfolgt bei den Vierquadrantenstellern Q4 und Q5 zu den Zeitpunkten t3 und t4, vgl. Fig. 3e und 3f, entsprechend der 4. und 5. Spannungsstufe in Fig. 3a. Im Zeitpunkt t5 wechselt der Vierquadrantensteller Q1 vom Schaltzustand Z1 in den Schaltzustand Z7 oder Z8 mit UQ = 0. Für die Vierquadrantensteller Q2 ... Q5 erfolgt dieser Uebergang zu den Zeiten t6 ... t9.At time t1, the four-quadrant controller Q2 changes from the switching state Z5 or Z6 by blocking the conductive thyristors T1 or T4 to the switching state Z2, cf. Fig. 3c, corresponding to the second voltage level in Fig. 3a. At time t2, the alternating current i1 changes its sign from "-" to "+", so that the four-quadrant actuators Q1 and Q2 change from the switching state Z2 to the switching state Z1 and the thyristors T1 and T4 replace the diodes D1 and D4 to conduct the alternating current i Q take over. At the same time, the four-quadrant Q3 switches. Fig. 3d, from the switching state Z5 or Z6 to the switching state Z1, corresponding to the third voltage level in Fig. 3a. The same switchover takes place for the four-quadrant actuators Q4 and Q5 at times t3 and t4, cf. 3e and 3f, corresponding to the 4th and 5th voltage level in Fig. 3a. At time t5, the four-quadrant controller Q1 changes from the switching state Z1 to the switching state Z7 or Z8 with U Q = 0. For the four-quadrant controllers Q2 ... Q5, this transition takes place at times t6 ... t9.

Für die negative Halbperiode der Wechselspannung U1 gilt Entsprechendes wie für die positive Halbperiode. Zum Zeitpunkt t9 und t10 wechseln die Vierquadrantensteller Q1 bzw. Q2 vom Schaltzustand Z7 oder Z8 in den Schaltzustand Z3 und nach dem Nulldurchgang des Wechselstromes i1 zum Zeitpunkt t11 in den Schaltzustand Z4. Die Vierquadrantensteller Q3 ... Q5 wechseln zu den Zeiten t11 ... t13 vom Schaltzustand Z7 oder Z8 in den Schaltzustand Z4. Zu den Zeiten t14 ... t18 wechseln die Vierquadrantensteller Q1 ... Q5 in den Schaltzustand Z5 oder Z6.The same applies to the negative half-cycle of AC voltage U1 as to the positive half-cycle. At times t9 and t10, the four-quadrant switches Q1 or Q2 from the switching state Z7 or Z8 to the switching state Z3 and after the zero crossing of the alternating current i1 at the time t11 to the switching state Z4. The four-quadrant controllers Q3 ... Q5 change from switching state Z7 or Z8 to switching state Z4 at times t11 ... t13. At times t14 ... t18, the four-quadrant controllers Q1 ... Q5 change to the switching state Z5 or Z6.

Folgende Schaltzustände sind gleichzeitig oder vorzugsweise abwechselnd benutzt, damit die stromdurchflossenen Halbleiterbauelemente möglichst gleichmässig ausgelastet und somit möglichst wenig erwärmt werden: Z5 mit Z6 und Z7 mit Z8. Bei entsprechender Ueberdimensionierung kann auf eine alternierende Ansteuerung verzichtet werden.The following switching states are used simultaneously or preferably alternately, so that the current-carrying semiconductor components are utilized as evenly as possible and are therefore heated as little as possible: Z5 with Z6 and Z7 with Z8. With corresponding oversizing, alternating control can be dispensed with.

Bei dem Ausführungsbeispiel gemäss Fig. 4 fehlen die Schaltzustände mit UQ = 0. Wie bei den Fig. 3b - 3f zeigen bei den Fig. 4b - 4f linksschraffierte Bereiche Schaltzustände in Vierquadrantenstellern an, in denen nur Dioden leiten. In rechtsschraffierten Bereichen leiten nur Thyristoren den Strom.In the exemplary embodiment according to FIG. 4, the switching states with U Q = 0 are missing. As in FIGS. 3b - 3f, areas hatched in the left in FIGS. 4b - 4f indicate switching states in four-quadrant actuators in which only diodes conduct. In right-hatched areas, only thyristors conduct the current.

Zu den Zeiten t19 - t22 werden die Vierquadrantensteller Q1 - Q4 nacheinander vom Schaltzustand Z4 in den Schaltzustand Z2 geschaltet. Im Zeitpunkt t23 ändert der Wechselstrom i1 sein Vorzeichen von "-" nach "+", und die Vierquadrantensteller Q1 - Q4 wechseln vom diodenleitenden Schaltzustand Z2 in den thyristorleitenden Schaltzustand Z1. Der Vierquadrantensteller Q5 wechselt vom thyristorleitenden Schaltzustand Z4 in den diodenleitenden Schaltzustand Z2. Im Zeitpunkt t24 ändert der Vierquadrantensteller Q5 vom Schaltzustand Z2 in den Schaltzustand Z1. Zu den Zeiten t25 - t28 werden bei den Vierquadrantenstellern Q1 - Q4 nacheinander die Thyristoren abgeschaltet, so dass diese vier Vierquadrantensteller in den Schaltzustand Z3 übergehen. Im Zeitpunkt t29 ändert der Wechselstrom i1 sein Vorzeichen von "+" nach "-", wobei die Vierquadrantensteller Q1 - Q4 in den Schaltzustand Z4 wechseln und der Vierquadrantensteller Q5 in den Schaltzustand Z2. Im Zeitpunkt t30 wechselt auch der Vierequadrantensteller Q5 in den Schaltzustand Z4.At times t19-t22, the four-quadrant actuators Q1-Q4 are switched in succession from the switching state Z4 to the switching state Z2. At time t23, the alternating current i1 changes its sign from "-" to "+", and the four-quadrant controllers Q1 - Q4 change from the diode-conducting switching state Z2 to the thyristor-conducting switching state Z1. The four-quadrant controller Q5 changes from the thyristor-conducting switching state Z4 to the diode-conducting switching state Z2. At time t24, the four-quadrant controller Q5 changes from the switching state Z2 to the switching state Z1. At times t25 - t28 at the four-quadrant actuators Q1 - Q4, the thyristors are switched off in succession, so that these four four-quadrant actuators pass into the switching state Z3. At time t29, the alternating current i1 changes its sign from "+" to "-", the four-quadrant controllers Q1-Q4 changing to the switching state Z4 and the four-quadrant controller Q5 to the switching state Z2. At time t30, the quadrant quadrant Q5 also switches to the switching state Z4.

Der Betrieb der Vierquadrantensteller gemäss Fig. 4 hat gegenüber demjenigen nach Fig. 3 den Vorteil, dass jeder Vierquadrantensteller während einer Periode der Wechselspannung U1 nur einmal ein- und ausgeschaltet wird. Dadurch reduzieren sich die Energieverluste im Vierquadrantensteller. Die Thyristorbeschaltung 17, insbesondere der Beschaltungswiderstand 19, kann für eine kleinere Leistung ausgelegt sein. Der Aufwand für die Kühlung der Halbleiterbauelemente ist reduziert. Die Ansteuerung der Thyristoren ist einfacher. Nachteilig ist die geringere Anzahl von Spannungsstufen, die eine schlechtere Angleichung an die gewünschte Sinusform der zu erzeugenden Wechselspannung U1 zur Folge hat. Bei genügender Anzahl von Vierquadrantenstellern und bei grossen Gesamtleistungen fällt dieses Problem nicht stark ins Gewicht. Ein weiterer Nachteil besteht in grösseren Energieverlusten in Eisenteilen der Transformatoren Tr1 ... Tr13, da die Vierquadrantensteller ohne Nullspannungs-Betriebszustand arbeiten. Dadurch muss jeder Teiltransformator praktisch immer bis zur Nenninduktivität belastet werden. Bei niedrigen Frequenzen, wie z.B. 16 2/3 Hz, fallen jedoch Eisenverluste weniger ins Gewicht. Vergleichsweise grössere Energieverluste treten in den Stromleitungen bzw. Stromschienen zwischen den Vierquadrantenstellern Q1 - Q13 und dem Gleichspannungszwischenkreis 10 auf. Im Unterschied dazu fliesst bei der Betriebsart gemäss Fig. 3 in den Nullspannungs-Schaltzuständen Z5 - Z8 kein Strom zum Zwischenkreis.The operation of the four-quadrant controller according to FIG. 4 has the advantage over that of FIG. 3 that each four-quadrant controller is only switched on and off once during a period of the AC voltage U1. This reduces the energy losses in the four-quadrant controller. The thyristor circuit 17, in particular the circuit resistor 19, can be designed for a lower power. The effort for cooling the semiconductor components is reduced. The control of the thyristors is easier. The disadvantage is the lower number of voltage levels, which results in poorer adaptation to the desired sinusoidal shape of the AC voltage U1 to be generated. With a sufficient number of four-quadrant digits and with large total outputs, this problem is not significant. Another disadvantage is the greater energy loss in the iron parts of the transformers Tr1 ... Tr13, since the four-quadrant actuators work without a zero-voltage operating state. As a result, each sub-transformer must practically always be loaded up to the nominal inductance. At low frequencies, such as 16 2/3 Hz, iron losses are less important. Comparatively larger energy losses occur in the power lines or busbars between the four-quadrant actuators Q1 - Q13 and the DC voltage intermediate circuit 10. In contrast to this, in the operating mode according to FIG. 3, no current flows to the intermediate circuit in the zero voltage switching states Z5-Z8.

Unter der vereinfachenden Annahme, dass Wechselstrom i1 und Wechselspannung U1 in den netzseitigen Wicklungen 1 des Spannungssummiertransformators Tr in Phase sind und der 13. Teiltransformator Tr13 als Momentanreserve an der Spannungsbildung unbeteiligt ist, sei die Betriebsweise der Stromrichterschaltung entsprechend Fig. 4 nochmals kurz erläutert. In einem gegebenen Zeitpunkt fliesse der Strom bei 7 von insgesamt 12 Vierquadrantenstellern durch jene Thyristoren, welche den Strom der positiven Halbschwingung führen können, Schaltzustand Z1. Wenn die Thyristoren der übrigen 5 Vierquadrantensteller sperren, wird der Stromfluss von ihren stellerseitigen Teiltransformatorwicklungen 2 über die Sperrdioden in den Plusteil des Gleichspannungszwischenkreises 10 erzwungen. Dazu müssen ihre Transformatorwicklungen 2 die notwendige Spannung aufbringen, welche höher als die Zwischenkreisspannung Ud ist. Bei einer Uebersetzung der Wicklungspaare 1, 2 von 1:1 wird in den netzseitigen Wicklungen 1 der betreffenden fünf Wicklungspaare eine Gegenspannung erzeugt, welche gleich gross ist. Damit entspricht die momentan induzierte Gesamtspannung U1 in den netzseitigen Wicklungen 1 des Spannungssummiertransformators Tr dem doppelten Wert der Zwischenkreisspannung Ud, nämlich 7 · Ud - 5 · Ud = 2 · Ud.Under the simplifying assumption that alternating current i1 and alternating voltage U1 are in phase in the line-side windings 1 of the voltage summing transformer Tr and the 13th partial transformer Tr13 is not involved as a momentary reserve in the voltage formation, the mode of operation of the converter circuit according to FIG. 4 is briefly explained again. At a given point in time, the current in 7 out of a total of 12 four-quadrant actuators flows through those thyristors which can carry the current of the positive half-oscillation, switching state Z1. When the thyristors of the remaining five four-quadrant actuators block, the current flow from their actuator-side partial transformer windings 2 is forced into the plus part of the DC voltage intermediate circuit 10 via the blocking diodes. For this purpose, their transformer windings 2 must apply the necessary voltage, which is higher than the intermediate circuit voltage Ud. With a translation of the winding pairs 1, 2 of 1: 1, a counter voltage is generated in the network-side windings 1 of the five winding pairs in question, which is of the same size. The currently induced total voltage U1 in the line-side windings 1 of the voltage summing transformer Tr thus corresponds to twice the value of the intermediate circuit voltage Ud, namely 7 · Ud - 5 · Ud = 2 · Ud.

Wenn nach einer entsprechenden Zeit die Thyristoren eines bis dahin gesperrten Vierquadrantenstellers gezündet werden, wird sein Strom von den Sperrdioden auf die Thyristoren kommutieren. Dabei ändert sich die Strompolarität dieses Vierquadrantenstellers in den Verbindungen zwischen Vierquadrantensteller und Gleichspannungszwischenkreis 10. Die Strompolarität in den Wicklungen des Spannungssummiertransformators Tr bleibt unverändert, und nur die Spannungspolarität des betreffenden Wicklungspaares wird geändert. Damit wird die neue, momentane, induzierte Gesamtspannung U1 in den netzseitigen Wicklungen 1 des Spannungssummiertransformators Tr einen Wert 8 · Ud - 4 · Ud = 4 · Ud von vierfacher Zwischenkreisspannung Ud erreichen. In weiteren entsprechenden Zeitabständen folgen Einschaltungen weiterer Thyristoren jener Vierquadrantensteller, welche bis dahin den Strom über Sperrdioden geleitet haben. Am Ende werden alle 12 Vierquadrantensteller den Strom über Thyristoren leiten. Zu diesem Zeitpunkt entspricht die momentane induzierte Gesamtspannung in den netzseitigen Wicklungen 1 des Spannungssummiertransformators Tr dem 12fachen Wert der Zwischenkreisspannung Ud.If after a corresponding time the thyristors of a four-quadrant controller which has been blocked until then are fired, its current will commutate from the blocking diodes to the thyristors. The current polarity of this four-quadrant controller changes in the connections between the four-quadrant controller and the DC link 10. The current polarity in the windings of the voltage summing transformer Tr remains unchanged, and only the voltage polarity of the relevant pair of windings is changed. The new, instantaneous, induced total voltage U1 in the line-side windings 1 of the voltage summing transformer Tr will thus reach a value 8 * Ud - 4 * Ud = 4 * Ud of four times the intermediate circuit voltage Ud. At further corresponding time intervals, further thyristors of those four-quadrant actuators which have previously conducted the current via blocking diodes are switched on. In the end, all 12 four-quadrant controllers will conduct the current via thyristors. At this point in time, the instantaneous total voltage induced in the line-side windings 1 of the voltage summing transformer Tr corresponds to 12 times the value of the intermediate circuit voltage Ud.

Auf die beschriebene Weise kann eine treppenförmige Spannungskurve von 0 bis zum Amplitudenwert in den netzseitigen Wicklungen 1 des Spannungssummiertransformators Tr gebildet werden. Der Abbau der induzierten Gesamtspannung in den netzseitigen Wicklungen 1 des Spannungssummiertransformators Tr vom Amplitudenwert bis Null erfolgt durch zeitlich verschobene Abschaltungen der Thyristoren jener Vierquadrantensteller, welche in den netzseitigen Wicklungen der zugehörigen Wicklungspaare die Spannungspolarität ändern und damit die Gesamtspannung reduzieren sollen. Die negative Halbschwingung wird entsprechend der positiven gebildet, wobei dann die für die negative Stromhalbschwingung zuständigen Thyristoren und Sperrdioden der Vierquadrantensteller aktiv werden.In the manner described, a step-shaped voltage curve from 0 to the amplitude value can be formed in the network-side windings 1 of the voltage summing transformer Tr. The reduction of the induced total voltage in the network-side windings 1 of the voltage summing transformer Tr from the amplitude value to zero is carried out by switching off the thyristors of those four-quadrant actuators which change the voltage polarity in the network-side windings of the associated winding pairs and thus to reduce the overall voltage. The negative half wave will formed in accordance with the positive, the thyristors and blocking diodes of the four-quadrant actuators responsible for the negative current half-oscillation then becoming active.

Da im reellen Betrieb die Ströme und Spannungen in den netzseitigen Wicklungen 1 des Spannungssummiertransformators Tr meist nicht in Phase sind, wird jeder Stromnulldurchgang immer eine Aenderung der momentanen Kombination der Vierquadrantensteller in bezug auf Stromführung durch Thyristoren bzw. Sperrdioden erforderlich machen.Since, in real operation, the currents and voltages in the line-side windings 1 of the voltage summing transformer Tr are usually not in phase, each current zero crossing will always require a change in the current combination of the four-quadrant actuators with respect to current carrying through thyristors or blocking diodes.

Eine Aenderung des Netzstromes i1 ist immer mit einer starr gekoppelten Stromänderung in allen Teiltransformatorwicklungspaaren 1, 2 verbunden. Dementsprechend kann der Spannungssummiertransformator Tr mit einer normalen Kurzschlusspannung von z.B. 5 % gebaut werden, wobei die Stromform nicht schlechter wird als bei einem gewöhnlichen Vierquadrantensteller, der mit einem Transformator mit erhöhter Kurzschlusspannung von z.B. 30 % gekoppelt ist und in der Arbeitsweise des Unterschwingungsverfahrens arbeitet. Dadurch lassen sich die Transformatorkosten sowie die Kupferverluste reduzieren, was zu einer Verbesserung des Gesamtwirkungsgrades führt.A change in the mains current i1 is always associated with a rigidly coupled current change in all partial transformer winding pairs 1, 2. Accordingly, the voltage summing transformer Tr can be operated with a normal short circuit voltage of e.g. 5% can be built, whereby the current shape is no worse than that of an ordinary four-quadrant converter, which is equipped with a transformer with an increased short-circuit voltage of e.g. 30% is coupled and works in the way of the undershoot method. This allows transformer costs and copper losses to be reduced, which leads to an improvement in the overall efficiency.

Jede Ein- oder Ausschaltung der Thyristoren von einem der 12 Vierquadrantensteller Q1 - Q12 bewirkt eine Aenderung des induzierten momentanen Gesamtspannungswertes in den netzseitigen Wicklungen 1 des Spannungssummiertransformators Tr entsprechend 1/6 des Amplitudenwertes. Dieser relativ kleine Spannungssprung muss eine Aenderung des Stromes in allen Wicklungen des Spannungssummiertransformators Tr bewirken. Dementsprechend werden die Streuinduktivitäten aller Wicklungen die Stromänderungen verlangsamen. Dadurch entsteht ein starker Stromglättungseffekt, welcher dazu beiträgt, dass die Stromform und damit auch die Spannungsform an den netzseitigen Ausgangsklemmen 3, 4 des Spannungssummiertransformators Tr weniger Oberschwingungen enthält und sich bei entsprechender Ansteuerung der Vierquadrantensteller der Sinuskurve besser anpassen lässt.Each time the thyristors are switched on or off by one of the 12 four-quadrant actuators Q1-Q12, the induced instantaneous total voltage value in the line-side windings 1 of the voltage summing transformer Tr changes according to 1/6 of the amplitude value. This relatively small voltage jump must cause a change in the current in all windings of the voltage summing transformer Tr. Accordingly, the leakage inductances of all windings become the changes in current slow it down. This creates a strong current smoothing effect, which contributes to the fact that the current form and thus also the voltage form at the line-side output terminals 3, 4 of the voltage summing transformer Tr contain fewer harmonics and can be better adapted to the sine curve if the four-quadrant controllers are controlled accordingly.

Das hier beschriebene System lässt auch die Möglichkeit zu, neben der Bildung der treppenförmigen Spannung diese auch fein zu regeln. Zu diesem Zweck müsste mindestens einer der Vierquadrantensteller in gewöhnlicher Ausführung für Taktbetrieb, d.h. mit aufwendiger Beschaltung, ausgeführt werden (z.B. die Reservestufe). Eine erhöhte Kurzschlusspannung des Teiltransformatorwicklungspaares 1, 2 dieses Vierquadrantenstellers Q13 ist nicht notwendig, da sich auch dieser Vierquadrantensteller nur zum Bruchteil an der Bildung des Gesamtspannungsmomentanwertes und an der Verzerrung des Gesamtstromes beteiligt.The system described here also allows the possibility of finely regulating the step-like tension in addition to the formation thereof. For this purpose, at least one of the four-quadrant controllers in the usual design for clock operation, i.e. with complex wiring (e.g. the reserve level). An increased short-circuit voltage of the partial transformer winding pair 1, 2 of this four-quadrant actuator Q13 is not necessary, since this four-quadrant actuator also participates only to a fraction in the formation of the total voltage instantaneous value and in the distortion of the total current.

Im Notbetrieb kann die Wechselspannung U1 auch ohne takten eines der Vierquadrantensteller durch Verlängerung der Stromführungsdauer einzelner Stufen geregelt werden. Dies bewirkt allerdings einen höheren Oberschwingungsanteil in der induzierten Spannungsgrundschwingung.In emergency operation, the alternating voltage U1 can also be regulated without clocking one of the four-quadrant actuators by extending the current carrying time of individual stages. However, this causes a higher harmonic component in the induced fundamental voltage oscillation.

Da die einzelnen Wicklungspaare 1, 2 des Spannungssummiertransformators Tr in der Arbeitsweise eines Stromwandlers arbeiten, muss sichergestellt werden, dass der Stromkreis keines der stellerseitigen Wicklungen 2 in Störungsfällen offen bleiben kann, z.B. wenn Thyristoren oder Sperrdioden eines Stellers defekt werden und dieser Stromkreis durch Sicherungen auf der Zwischenkreisund Transformatorseite vom System getrennt wird. Zu diesem Zweck wird zu jeder stellerseitigen Transformatorwicklung 2 ein Thyristorkurzschliesser 5 für beide Stromrichtungen installiert. Die Thyristoren des Kurzschliessers 5 müssen auf jeden Fall automatische, selbstzündende Notzündkreise haben, welche den Kurzschliesser bei einer Ueberschreitung einer vorgebbaren Höchstspannung automastisch leitend machen. Diese Höchstspannung muss etwas höher als die maximale Betriebsspannung des Gleichspannungszwischenkreises 10 liegen. Die Realisierung der Notzündkreise wird meistens, wie allgemein bekannt, mit Hilfe von Kippdioden gelöst, welche beim Erreichen einer bestimmten Spannung leitend werden und den Thyristor über den normalen Zündkreis zünden.Since the individual winding pairs 1, 2 of the voltage summing transformer Tr operate in the manner of a current transformer, it must be ensured that the circuit none of the actuator-side windings 2 can remain open in the event of a fault, for example if thyristors or blocking diodes of an actuator become defective and this circuit is opened by fuses the DC link and transformer side are separated from the system. To this For this purpose, a thyristor short-circuiting device 5 is installed for each current transformer side 2 for both current directions. The thyristors of the short-circuiting device 5 must in any case have automatic, self-igniting emergency ignition circuits, which make the short-circuiting device automatically conductive when a predetermined maximum voltage is exceeded. This maximum voltage must be somewhat higher than the maximum operating voltage of the DC link 10. The realization of the emergency ignition circuits is usually, as is generally known, solved by means of breakover diodes, which become conductive when a certain voltage is reached and ignite the thyristor via the normal ignition circuit.

Neben den Notzündkreisen können die Kurzschliesser-Thyristoren mit zusätzlichen Zündkreisen ausgerüstet werden, welche jederzeit eine gewünschte Zündung erlauben. Damit können die Wechselstromschalter 5 alternativ zu Regelzwecken verwendet werden, und zwar bei der Nullspannungsbildung UQ = 0 eines Vierquadrantenstellers, entsprechend den Schaltzuständen Z5 - Z8. Dabei wird der Wechselstromschalter 5 während der entsprechenden Zeitintervalle eingeschaltet. Gleichzeitig entfallen die sonst für die Schaltzustände Z5 - Z8 erforderlichen Zündsignale für die Vierquadrantensteller.In addition to the emergency ignition circuits, the short-circuiting thyristors can be equipped with additional ignition circuits, which allow the desired ignition at any time. The AC switches 5 can thus be used as an alternative for control purposes, specifically when the zero voltage formation U Q = 0 of a four-quadrant actuator, corresponding to the switching states Z5-Z8. The AC switch 5 is switched on during the corresponding time intervals. At the same time, the ignition signals for the four-quadrant actuators otherwise required for the switching states Z5 - Z8 are omitted.

Da beim Wechselstromschalter 5 jeweils nur ein Halbleiterbauelement stromführend ist, im Vergleich zu zwei stromführenden Halbleiterbauelementen in den Schaltzuständen Z5 - Z8, reduzieren sich die Energieverluste während dieser Zeitintervalle.Since in the AC switch 5 only one semiconductor component is live in comparison to two current-carrying semiconductor components in the switching states Z5-Z8, the energy losses are reduced during these time intervals.

Im allgemeinen wird die Höhe der Wechselspannung eines Vierquadrantenstellers entweder durch Regelung der Zwischenkreisgleichspannung Ud, z.B. durch Anschnittsteuerung des netzgeführten 50-Hz-Speisestromrichters 15 oder durch einen einzigen der Vierquadrantensteller, welcher im Taktbetrieb mit höherer Frequenz arbeitet, geregelt. Die Ansteuerung der übrigen Vierquadrantensteller wird von einer anderen Regelung bedient, welche für Spannungsform und Phasenlage am netzseitigen Ausgang des Spannungssummiertransformators Tr verantwortlich ist.In general, the level of the AC voltage of a four-quadrant controller is either regulated by the DC link voltage Ud, for example, by gate control of the mains-operated 50 Hz feed converter 15 or by a single one of the four-quadrant controllers, which operates in clock mode at a higher frequency. The control of the remaining four-quadrant actuators is operated by another control which is responsible for the voltage form and phase position at the network-side output of the voltage summing transformer Tr.

Gewerbliche VerwertbarkeitCommercial usability

Die erfindungsgemässe Stromrichterschaltung ist zur Energieübertragung in beiden Richtungen, d.h. vom Wechselspannungsnetz N1 ins Wechselspannungsnetz N2 und umgekehrt geeignet, vorzugsweise im Leistungsbereich von 5 MW - 20 MW. Beide Netze können selbstverständlich mehrphasig sein. In diesem Fall ist für jede Phase des Wechselstromes ein Spannungssummiertransformator Tr mit Teiltransformatoren Tr1 ... Tr13 und zugehörigen Stromrichtern Q1 ... Q13 und Wechselstromschaltern 5 vorzusehen. Es können auch mehr oder weniger als 13 Teiltransformatoren je Spannungssummiertransformator Tr verwendet werden.The converter circuit according to the invention is for energy transmission in both directions, i.e. from alternating voltage network N1 to alternating voltage network N2 and vice versa, preferably in the power range from 5 MW to 20 MW. Both networks can of course be multi-phase. In this case, a voltage summing transformer Tr with partial transformers Tr1 ... Tr13 and associated converters Q1 ... Q13 and AC switches 5 must be provided for each phase of the alternating current. It is also possible to use more or fewer than 13 sub-transformers per voltage summing transformer Tr.

Die Stromrichterschaltung kann auch für Frequenzumformer dreiphasiger Netze verwendet werden, z.B. 50 Hz/60 Hz oder 60 Hz/25 Hz usw.The converter circuit can also be used for frequency converters of three-phase networks, e.g. 50 Hz / 60 Hz or 60 Hz / 25 Hz etc.

Statt gewöhnlicher Thyristoren im Wechselstromschalter 5 können auch abschaltbare GTO-Thyristoren oder, für kleinere Ströme, Transistoren verwendet werden. Statt GTO-Thyristoren im Vierquadrantensteller können selbstverständlich gewöhnliche Thyristoren mit Löschkreisen oder Transistoren verwendet werden. Bei Bedarf können mehrere Thyristoren in Reihe und/oder parallelgeschaltet sein.Instead of conventional thyristors in the AC switch 5, it is also possible to use GTO thyristors which can be switched off or, for smaller currents, transistors. Instead of GTO thyristors in the four-quadrant controller, ordinary thyristors with quenching circuits or transistors can of course be used. If required, several thyristors can be connected in series and / or in parallel.

Mit der Stromrichterschaltung ist, unabhängig von der Energieübertragungsrichtung, eine Leistungsübertragung im kapazitiven und induktiven Bereich möglich, d.h., sie ist auch als Blindleistungskompensator einsetzbar. Die Stromrichterschaltung kann parallel zu anderen Spannungsquellen im Netz betrieben werden. Die Arbeit der Stromrichterschaltung von praktisch Null- bis Vollast ist ohne drastische Wirkungsgradreduktion und ohne wesentliche Erhöhung des Oberschwingungsanteils möglich.Regardless of the direction of energy transmission, the converter circuit enables power transmission in the capacitive and inductive range, i.e. it can also be used as a reactive power compensator. The converter circuit can be operated in parallel with other voltage sources in the network. The converter circuit can work from practically zero to full load without drastically reducing efficiency and without significantly increasing the harmonic content.

Claims (7)

  1. Process for controlling a static converter circuit
    a) which is effectively connected to a voltage summing transformer (Tr) which has several magnetically decoupled part transformers (Tr1 - Tr13), each part transformer having at least one power-system-side winding (1) and at least one static-converter-side winding (2),
    b) the power-system-side windings (1) of the part transformers being connected in series and
    c) the static-converter-side winding (2) of each part transformer (Tr1 - Tr13) being effectively connected to a static converter (Q1 - Q13)
    d) for generating an at least approximately sinusoidal alternating voltage (U1) with a predeterminable frequency, the amplitude of the fundamental oscillation of this alternating voltage being formed in voltage steps by step-by-step addition and/or subtraction of part-voltages and/or direct-voltages of equal magnitude (Ud),
    e) the beginning and end of each voltage step being staggered in time in such a manner that the stairstep shape generated by the voltage steps is matched to the sinusoidal shape,
    f) each part voltage (Ud) being generated by a separate part voltage source (Tr1, Q1; Tr2, Q2; ... Tr13, Q13) and
    g) the part-voltage sources being turned off in the same order in which they were turned on for forming the stairstep shape,
    characterised
    h) in that an electric valve (5) which is connected in parallel with the alternating-voltage connection (6, 7) of the static converter (Q1-Q13) is made conductive in each case after a thyristor (T1 - T4) of a static converter (Q1 - Q13) has been turned off.
  2. A process according to Claim 1, characterised in that one of the static converters (Q13) is pulsed at a higher frequency than the other static converters (Q1 - Q12) for finely controlling the stairstep-shaped voltage.
  3. A process according to Claim 1 or 2, characterised in that alternative current branches and/or switching states (Z5, Z6; Z7, Z8) of a static converter (Q1 - Q13) are alternately triggered, so as to thermally load the semi-conductor components, through which current flows, as evenly as possible.
  4. Static converter circuit
    a) which is effectively connected to a voltage summing transformer (Tr) which has several magnetically decoupled part transformers (Tr1 - Tr13), each part transformer having at least one power-system-side winding (1) and at least one static-converter-side winding (2),
    b) the power-system-side windings (1) of the part transformers being connected in series and
    c) the static-converter-side winding (2) of each part transformer (Tr1 - Tr13) being effectively connected to a static converter (Q1 - Q13)
    d) each static converter circuit (Q1 - Q13) having a single-phase bridge circuit with one gate-turn-off thyristor (T1 - T4) each per bridge branch,
    characterised
    e) in that a diode (D1 - D4) is connected in anti-parallel with each thyristor of this bridge circuit and
    f) in that at least one alternating-current circuit breaker (5) is connected in parallel with the alternating voltage connection of each static converter (Q1 - Q13).
  5. Static converter circuit according to Claim 4, characterised in that the alternating-current circuit breaker is a thyristor-type alternating-current circuit breaker (5).
  6. Use of the static converter circuit according to Claim 4 or 5 for a frequency converter.
  7. Use of the static converter circuit according to Claim 4 or 5 for a reactive-power compensator.
EP87109676A 1986-08-01 1987-07-06 Rectifier circuit and method for its controling Expired - Lifetime EP0254911B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT87109676T ATE77019T1 (en) 1986-08-01 1987-07-06 POWER CONVERTER CIRCUIT AND METHOD FOR CONTROLLING IT.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH3102/86 1986-08-01
CH310286 1986-08-01

Publications (2)

Publication Number Publication Date
EP0254911A1 EP0254911A1 (en) 1988-02-03
EP0254911B1 true EP0254911B1 (en) 1992-06-03

Family

ID=4248663

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87109676A Expired - Lifetime EP0254911B1 (en) 1986-08-01 1987-07-06 Rectifier circuit and method for its controling

Country Status (5)

Country Link
US (1) US4800481A (en)
EP (1) EP0254911B1 (en)
AT (1) ATE77019T1 (en)
DE (1) DE3779506D1 (en)
NO (1) NO172467C (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4225269A1 (en) * 1992-07-31 1994-02-03 Asea Brown Boveri Network harmonic attenuation method and a network coupling
DE4303317A1 (en) * 1993-02-05 1994-08-11 Abb Management Ag Converter bridge

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4979019A (en) * 1988-05-11 1990-12-18 Refractory Composites, Inc. Printed circuit board with inorganic insulating matrix
DE3934836A1 (en) * 1989-10-19 1991-04-25 Asea Brown Boveri ARRANGEMENT FOR CONVERTING TWO SINGLE-PHASE ALTERNATING CURRENTS INTO A SYMMETRIC THREE-PHASE CURRENT
DE4037531C2 (en) * 1990-11-26 2003-11-06 Daimlerchrysler Rail Systems Method for controlling rectifiers
DE19647933A1 (en) * 1996-11-20 1998-05-28 Asea Brown Boveri Static power converter for railway traction current supply
US6216218B1 (en) * 1997-11-03 2001-04-10 Donald L. Sollars Processor having a datapath and control logic constituted with basis execution blocks
FR2777399B1 (en) * 1998-04-09 2000-06-09 Centre Nat Rech Scient METHOD AND DEVICE FOR CONTROLLING A STATIC CONVERTER SUPPLYING A CURRENT SOURCE
US6198178B1 (en) 1999-12-21 2001-03-06 International Power Systems, Inc. Step wave power converter
US6738692B2 (en) 2001-06-25 2004-05-18 Sustainable Energy Technologies Modular, integrated power conversion and energy management system
CN1190885C (en) * 2001-08-07 2005-02-23 任少康 Waveform generation method and power converter device
DE10330473A1 (en) * 2003-07-05 2005-01-27 Alstom Technology Ltd Frequency converter for high-speed generators
DE102004028166A1 (en) * 2004-06-09 2006-01-05 Krämer, Alexander, Dr. Method for the construction of a system network
US7808125B1 (en) 2006-07-31 2010-10-05 Sustainable Energy Technologies Scheme for operation of step wave power converter
CA2689503C (en) * 2007-06-04 2017-05-09 Sustainable Energy Technologies Prediction scheme for step wave power converter and inductive inverter topology
JP2009095202A (en) * 2007-10-12 2009-04-30 Daikin Ind Ltd Inverter
DE102008007658A1 (en) * 2008-02-06 2009-08-13 Siemens Aktiengesellschaft Static converter
CN104410290A (en) * 2014-12-08 2015-03-11 重庆瑜欣平瑞电子有限公司 Frequency converter for digital power generator
KR102117489B1 (en) * 2016-09-14 2020-06-02 패러데이 그리드 리미티드 Power distribution network and power distribution method

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3477016A (en) * 1966-08-15 1969-11-04 George Ioannon Papaleonidas Transformer system including a large number of magnetically independent transformer elements
US3622862A (en) * 1970-10-22 1971-11-23 Asea Ab By-pass connection of static converters
US3938031A (en) * 1974-09-03 1976-02-10 Robicon Corporation Adjustable voltage power supply
US4159513A (en) * 1977-09-30 1979-06-26 Westinghouse Electric Corp. Static controlled AC motor drive having plug reversal capability
US4663702A (en) * 1984-10-12 1987-05-05 Kabushiki Kaisha Toshiba Power converter apparatus and control method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4225269A1 (en) * 1992-07-31 1994-02-03 Asea Brown Boveri Network harmonic attenuation method and a network coupling
DE4303317A1 (en) * 1993-02-05 1994-08-11 Abb Management Ag Converter bridge

Also Published As

Publication number Publication date
NO172467B (en) 1993-04-13
NO873087L (en) 1988-02-02
EP0254911A1 (en) 1988-02-03
US4800481A (en) 1989-01-24
DE3779506D1 (en) 1992-07-09
NO172467C (en) 1993-07-21
ATE77019T1 (en) 1992-06-15
NO873087D0 (en) 1987-07-22

Similar Documents

Publication Publication Date Title
EP0254911B1 (en) Rectifier circuit and method for its controling
DE69611176T2 (en) METHOD AND DEVICE FOR THE CONTINUOUSLY ADJUSTMENT AND REGULATION OF THE TURN RATIO OF A TRANSFORMER AND TRANSFORMER WITH SUCH A DEVICE
EP2282399B1 (en) Static converter and method for starting the converter
EP0166954B1 (en) Method for the reduction of dynamic overvoltages in an alternating current grid system
EP0152002B1 (en) Phase-shifter
EP2088668A2 (en) Static convertor
EP0852841B1 (en) Mains-adapted voltage-applying high-output oblique transformer controlled by a current converter
EP3656032B1 (en) Series compensation device
DE3724526A1 (en) RECTIFIER CIRCUIT FOR SUPPLYING A DC INTERMEDIATE CIRCUIT
EP3531547A1 (en) Operating circuit for coupling of a synchronous machine with a voltage network and method for the operation of same
AT406993B (en) THREE-PHASE PULSE RECTIFIER SYSTEM WITH HIGH-FREQUENCY POTENTIAL ISOLATED OUTPUT VOLTAGE
DE2913622A1 (en) CIRCUIT ARRANGEMENT OF A HIGH POWER DIAGNOSTIC ROENTINE EQUIPMENT WITH A THYRISTOR POWER CONVERTER
DE2909686A1 (en) DEVICE FOR SUPPLYING USERS IN A RAILWAY VEHICLE
DE3907940A1 (en) Method for symmetrising the voltage sharing in power converters having multi-point connection
DE2738562A1 (en) CONVERTERS FOR SUPPLYING SYNCHRONOUS MACHINES
DE102016223944A1 (en) Plant for transmitting electrical power
DE2433825B2 (en) Devices for supplying energy and improving the power factor of AC networks
DE685162C (en) Arrangement for regulating the reactive power in an alternating current network
DE2804481A1 (en) Control circuit with bidirectional thyristor arrangement - controlling reactive power of capacitor connected to AC mains
EP0053294B1 (en) Energy supply device for a passenger-train car
AT702U1 (en) FREQUENCY CONVERTER
DE920738C (en) Circuit for converting three-phase current into single-phase current of low frequency
DE19703440A1 (en) Device for direct current supply for an electric melting unit
DE700744C (en) Converter system with an additional device to enable any ignition times
DE648678C (en) Device for block feeding of single-phase alternating current railways by means of a converter

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT CH DE LI SE

17P Request for examination filed

Effective date: 19880730

17Q First examination report despatched

Effective date: 19900731

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT CH DE LI SE

REF Corresponds to:

Ref document number: 77019

Country of ref document: AT

Date of ref document: 19920615

Kind code of ref document: T

REF Corresponds to:

Ref document number: 3779506

Country of ref document: DE

Date of ref document: 19920709

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
EAL Se: european patent in force in sweden

Ref document number: 87109676.4

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 20000616

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 20000622

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 20000626

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20000629

Year of fee payment: 14

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20010706

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20010707

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20010731

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20010731

EUG Se: european patent has lapsed

Ref document number: 87109676.4

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20020501